Current wireless mobile communication devices include microprocessors, memory, soundcards, speakers, headphones, and run one or more software applications in addition to providing for voice communications. Examples of software applications used in these wireless devices include browsers, address books, email, instant messaging (“IM”), and mobile hotspot functions. Additionally, wireless devices have access to a plurality of services via the Internet. A wireless device may, for example, be used to browse web sites on the Internet, to transmit and receive graphics, and to execute streaming audio and/or video applications. Such wireless devices may operate on a cellular network (e.g., GSM), on a wireless local area network (“WLAN”) (e.g., IEEE 802.11), on a Bluetooth network (e.g., IEEE 802.15.1), or on all of these types of networks.
One problem with current wireless devices pertains to simultaneous WLAN and Bluetooth communications. During such communications, interference may arise between WLAN signal reception and Bluetooth signal (e.g., voice) transmission. In particular, the front-end radio frequency (“RF”) architectures of some wireless devices allow for simultaneous Bluetooth and WLAN operation. An example of such an architecture is one where each of the WLAN and Bluetooth radios has its own antenna. Bluetooth includes adaptive frequency hopping (“AFH”) functionality which reduces co-channel interference. However, during simultaneous Bluetooth transmission (“TX”) and WLAN reception (“RX”), adjacent channel interference (“ACI”) continues to be a serious problem. Reducing the Bluetooth TX power level and increasing the Bluetooth to WLAN antenna isolation can help in reducing ACI but it is often not helpful enough.
One key metric of WLAN receiver performance is automatic gain control (“AGC”) which is used to regulate the received signal strength at the input of the analog-to-digital converter (“ADC”) within the wireless device such that the required signal-to-noise ratio (“SNR”) for proper decoding is met. In the presence of strong ACI, better performance is obtained by reducing the level of AGC. This however has the effect of reducing receiver sensitivity, that is, only WLAN frames with higher SNR values will be decoded correctly. This trade-off is not present in the absence of ACI and maintaining AGC at a high value is recommended for improved WLAN receiver performance.
A need therefore exists for an improved method and system for adjusting receiver gain in a WLAN radio of a wireless device supporting simultaneous WLAN and Bluetooth communications. Accordingly, a solution that addresses, at least in part, the above and other shortcomings is desired.
It will be noted that throughout the appended drawings, like features are identified by like reference numerals.